What is 254 smo stainless steel?
254 SMO is a super austenitic stainless steel (UNS S31254) with high strength and excellent resistance to pitting corrosion, crevice corrosion, and stress corrosion cracking, making it particularly suitable for chloride-rich environments such as seawater. Its high molybdenum, nickel, chromium, and nitrogen content makes it a durable and reliable choice for demanding applications, commonly used in industries such as shipbuilding, chemicals, pulp and paper.
What is SMO 254 material equivalent to?
The main material equivalent for 254 SMO stainless steel is UNS S31254, but other designations include Werkstoff NR 1.4547 (German), SIS 2378 (Swedish), and EN X1CrNiMoCuN20-18-7 (European). These all refer to the same high-alloy austenitic stainless steel with excellent corrosion resistance.
| UNS | EN | ASTM | Other |
|---|---|---|---|
| S31254 | 1.4547 (X1CrNiMoN20-18-7) | F44 | 254SMO |
Chemical Composition (weight %)
| Element | Min % | Max % |
|---|---|---|
| Carbon (C) | – | 0.020 |
| Chromium (Cr) | 19.50 | 20.50 |
| Nickel (Ni) | 17.50 | 18.50 |
| Molybdenum (Mo) | 6.00 | 7.00 |
| Nitrogen (N) | 0.18 | 0.25 |
| Copper (Cu) | 0.50 | 1.00 |
| Manganese (Mn) | – | 1.00 |
| Silicon (Si) | – | 0.70 |
| Phosphorus (P) | – | 0.030 |
| Sulfur (S) | – | 0.010 |
| Iron (Fe) | Balance | Balance |
PREn (Pitting Resistance Equivalent) = %Cr + 3.3×%Mo + 16×%N = 42-4
Mechanical Properties
UNS S31254 (254SMO) / 1.4547 / F44 offers an excellent combination of strength, ductility, and toughness. These properties make it suitable for demanding applications where both mechanical performance and corrosion resistance are required.
| Property | Sheet & Strip | Plate |
|---|---|---|
| Tensile Strength (min) | 100 ksi (690 MPa) | 95 ksi (655 MPa) |
| 0.2% Yield Strength (min) | 45 ksi (310 MPa) | 45 ksi (310 MPa) |
| Elongation (min) | 35% in 50mm | 35% in 50mm |
| Hardness (max) | 223 HB / 96 HRB | 223 HB / 96 HRB |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.0 kg/dm³ |
| Modulus of Elasticity at 20°C | 195 GPa |
| Mean Coefficient of Thermal Expansion (20-100°C) | 16.5 × 10⁻⁶ K⁻¹ |
| Thermal Conductivity at 20°C | 14 W·m⁻¹·K⁻¹ |
| Specific Thermal Capacity at 20°C | 500 J·kg⁻¹·K⁻¹ |
| Electrical Resistivity at 20°C | 0.85 Ω·mm²·m⁻¹ |
| Magnetisable | No (except when cold worked) |
What is the difference between SMO 254 and ss316?
SMO 254 is a super austenitic stainless steel with a higher molybdenum and nitrogen content, making it superior to SS316 in corrosion resistance (especially in high-chloride environments), strength, and high-temperature performance. SS316 is a more common, less expensive austenitic stainless steel that is suitable for many applications but lacks the robust resistance of SMO 254 in harsh conditions like seawater or chemical plants.
If you have any project needs for SMO 254 stainless steel, please feel free to place an order. GNEE has a large inventory of popular products for you to choose from. It can be processed into various practical product forms, including plates, coils, pipes, bars, and wires. For detailed chemical composition and free samples, please contact our factory immediately. We offer competitive prices and excellent service.
| Product Form | Dimensions / Range |
|---|---|
| Sheet & Coil | Thickness: 0.5 – 6.0 mm Width: 500 – 2000 mm Length: Up to 6000 mm or coil form |
| Plate | Thickness: 6.0 – 100 mm Width: 1000 – 3000 mm Length: 2000 – 12000 mm |
| Round Bar | Diameter: 6 – 300 mm Length: Up to 6000 mm |
| Flat Bar | Thickness: 5 – 100 mm Width: 10 – 300 mm Length: Up to 6000 mm |
| Pipe & Tube | Outside Diameter: 6 – 325 mm Wall Thickness: 0.5 – 20 mm Length: Up to 12000 mm |
| Forgings | Custom dimensions available upon request |
| Flanges | According to standard specifications or custom requirements |
